Drafting instrument.



4 u 888,709. PATENTED MAY. 26, 1908. v. HIGGINS, E. W. DAVIS & F. H. ATKINSON.

DRAFTING INSTRUMENT.-

- APPLICATION FILED JUNE 4, 1907 I/Ifllllflilll! THE "cams Finns cm, WASNINGYDN. c.

UNITED STATES PATENT OFFICE.

VICTOR HIGGINS, ELMER W. DAVIS, AND FRANK H. ATKINSON, OF CHICAGO, ILLINOIS.

DRAFTING INSTRUMENT.

Specification of Letters Patent.

Patented May 26, 1908.

To all whom it may concern:

Be it known that we, VIoToR HIGGINS, ELMER WV. DAVIS, and FRANK H. ATKINSON, citizens of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvements in Drafting Instruments, of which the following is a specification.

This invention relates to a drafting instrument especially adapted for sign painters, scenic artists, decorators or workers inother crafts, whereby one or any desired number of concentric ellipsoids can be quickly drawn with but one setting of the focal points.

The invention has for one of its objects to improve and simplify the construction and operation of devices of this character so as to be comparatively easy and inexpensive to manufacture, highly eflicient and satisfactory in use, composed of few parts, and of such size as to be conveniently carried in the pocket when not in use.

A further object of the invention is the provision of a drawing instrument including a flexible element ada ted to be fixed at the focal points of the e 'psoid or oval to be drawn and on which travels a device having an extensible member such as a tape, which can be drawn out to different distances to enable a plurality of concentric ellipses to be drawn with but one setting of the focal points, the tape or extensible member being provided with a holder for a pencil or brush for describing the ellipsoids.

I/Vith these objects in view and others, as will appear as the description proceeds, the invention comprises the various novel features of construction and combination of arts which will be more fully described here- Inafter and set forth with particularity in the claims appended hereto.

In the accompanying drawing, which illustrates one of the embodiments of the invention, Figure 1 is a longitudinal sectional view with the parts in elevation. Fig. 2 is a transverse section on line 22, Fig. 1. Fig. 3 is a view showing the manner of describing ellipsoids or ovals with the device.

Similar reference characters are employed to designate corresponding parts throughout the several views.

The present invention depends for its operation upon the principle of drawing an e lipsoid by means of a cord or flexible element having its ends fastened at the focal points of the ellipsoid to be drawn, the pencil or suitable marker being guided by means of the flexible cord as the operator moves the pencil in a circular direction while maintaining the cord taut at all points.

The drafting device comprises a flat body 1 of brass or other suitable metal that is chambered out to receive the working parts of the device, a top plate 2 being provided for covering the body and forming therewith a housing. In one portion of the chamber 3 is a drum 4 that rotates on a fixed shaft 5 and is provided with a notched wheel 6; l/Vithin the drum 4 is a spiral spring 7 anchored at one end to the shaft or axle 5, and at the other end to the drum 4. Wound on the drum is a steel tape or other flexible member 8 that passes out through a slot 9 in the body 1, the spring 7 being so arranged as to hold the tape indrawn and wound on the drum. Arranged in the chamber 3 and with a portion extending out of the opening 10 is a pivoted pawl or catch 11 adapted to engage the notches 12 in the periphery of the wheel 6, the portion of the pawl extending through the opening 10 being serrated at 13 to provide a gripping surface whereby the thumb can readily release the pawl. The pawl is pressed by a spring 14 anchored around lugs or posts 15 on the body 1 and operating to maintain the pawl in locking position. By pressing on the pawl in such a manner as to compress the spring, the pawl will be disengaged from the wheel so that the tape can be drawn upwardly and by releasing the pawl, it will immediately engage the adjacent notch 12 of the wheel 6 and prevent the tape from being indrawn. The outer end of the tape is provided with a head 16 on which is swiveled a ring 17 to constitute a holder for a pencil or brush point and the head prevents the tape from being drawn completely within the housing. At a point diametrically opposite from the tape is a trolley or grooved wheel 18 mounted by means of a ball bearing 19 on a post 20- disposed between the top plate and body,whereby the device can be freely moved along the cord or flexible element 21 which guides the device in' the path of an ellipsoid.

In practice, a cord, wire or other flexible element of any desired length is selected, according to the nature of the work to be done. The ends of the flexible element are fastened by means of tacks, nails or other fasteners at the focal points of the ellipsoid or ellipsoids to be drawn, the device being threaded on the flexible element before the ends are attached to the focal points. The tape 8 is then drawn out to such a point as to enable an ellipsoid of the desired size to be drawn and then a pencil or other marker is inserted in the ring 17 and the pencil moved in a circular direction with a simultaneous pull outwardly so as to maintain the flexible element 21 taut. It is preferable to begin with a point in line with the major axis of the ellipsoid and after one half of the ellipsoid has been drawn, the device is turned over so as to prevent twisting of the flexible element, the swivel joint between the ring and tape readily permitting the device to be turned over while maintaining the pencil or marker in proper position with respect to the surface on which the ellipsoid is drawn. The other half of the ellipsoid is then finished in the same manner. To draw a second ellipsoid, the tape 9 is drawn out a distance equal to half the difference between the maj or axis of the two ellipsoids and the second concentric ellipsoid drawn, as before. In this manner, any desired number of parallel ellipsoids can be made, as illustrated in Fig. 3, wherein 22 are the focal points; 2], the flexible guiding cord; 24, the tape carrying device; and 8, the tape. In practice, it has been found that ellipsoids varying from a few inches to fifty or one hundred feet can be conveniently and quickly made by properly selecting the length of the guiding cord, and this with a device that can be readily carried in the vest pocket when not in use. By means of the tape or extensible member, a plurality of ellipsoids can be drawn with but one setting of the focal points. It will thus be seen that the operation of making ellipsoids is com paratively simple and expeditious.

From the foregoing description, taken in connection with the accompanying drawings, the advantages of the construction and of the method of operation will be readily apparent to those skilled in the art to which the invention appertains, and while we have described the principle of operation of the invention, together with the apparatus which we now consider to be the best embodiment thereof, we desire to have it understood that the apparatus shown is merely illustrative and that such changes may be made when desired, as are within the scope of the claims.

Having thus described the invention, what we claim is 1. An instrument of the class described comprising a flexible guiding element of constant length adapted to be secured at the l focal points on an ellipsoid to be drawn, with l a device movable along the element and including a member adapted to be lengthened or shortened for permitting a plurality of concentric ellipsoids to be made.

2. In an apparatus of the class described, the combination of a flexible guiding element adapted to be secured at the focal points of an ellipsoid, with a device movable along the element, said device comprising a holder for a marker, and means for varying the position of the holder for drawing eoncentric ellipsoids.

3. In an apparatus of the class described, the combination of a flexible guiding element of fixed length adapted to have its ends secured, an ellipsoid drawing device movable along the element, said device comprising a body, an anti-friction means engaging the element, a marker holder located at a point opposite from the anti-friction means, and an extensible and retractible member connecting the holder with the body.

4. In an apparatus of the class described, the combination of a flexible guiding element, with an ellipsoid marking device movable on the same, said device comprising a body, a trolley mounted on the body to engage the element, a marker holder, and a flexible connection between the holder and body.

5. In an apparatus of the class described, the combination of a flexible guiding element, with an ellipsoid marking device movable on the same, said device comprising a body, a trolley mounted on the body to enthe element, a marker holder, a flexible member on the body and connected with the holder for permitting the same to be. adjusted for making ellipsoids of different sizes, and a locking device controlling the flexible member.

6. A. device of the class described comprising a chambered body, a spring-actuated drum therein, a flexible member adapted to wind on the drum, a marker holder, a swiveled joint between the holder and one extremity of the flexible member, a locking device for holding the drum in set position, and means for attaching the device to a flexible guiding element.

In testimony whereof, we affix our signatures in presence of two witnesses.

VICTOR HIGGINS. ELMER W. DAVIS. FRANK H. ATKINSON. IVitnesses:

K. ALLEN, C. Bnanwiu'. 

